w3resource

Java String Exercises: Concatenate a given string with itself of a given number of times

Java String: Exercise-106 with Solution

Write a Java program to concatenate a given string with itself of a given number of times.

Sample Solution:

Java Code:

import java.util.Arrays;
public class Main {    
    public static void main(String[] args) {
        String str1 = "PHP";
        System.out.println("Original string: "+str1);
        String resultV1 = repeat_str(str1, 7);
       System.out.println("\nAfter repeating 7 times: "+resultV1);
   }
public static String repeat_str(String str1, int n) {
       if (str1 == null || str1.isEmpty()) {
           return "";
       }
       if (n <= 0) {
           return str1;
       }
       if (Integer.MAX_VALUE / n < str1.length()) {
           throw new OutOfMemoryError("Maximum size of a String will be exceeded");
       }
       StringBuilder x = new StringBuilder(str1.length() * n);
       for (int i = 1; i <= n; i++) {
           x.append(str1);
       }
       return x.toString();
   }
}

Sample Output:

Original string: PHP

After repeating 7 times: PHPPHPPHPPHPPHPPHPPHP

Pictorial Presentation:

Java String Exercises: Concatenate a given string with itself of a given number of times

Flowchart:

Flowchart: Java String Exercises - Concatenate a given string with itself of a given number of times.

Java Code Editor:

Improve this sample solution and post your code through Disqus

Previous: Write a Java program to count the occurrences of a given string in another given string.
Next: Java Date, Time and Calendar Exercises

What is the difficulty level of this exercise?



Java: Tips of the Day

Array vs ArrayLists:

The main difference between these two is that an Array is of fixed size so once you have created an Array you cannot change it but the ArrayList is not of fixed size. You can create instances of ArrayLists without specifying its size. So if you create such instances of an ArrayList without specifying its size Java will create an instance of an ArrayList of default size.

Once an ArrayList is full it re-sizes itself. In fact, an ArrayList is internally supported by an array. So when an ArrayList is resized it will slow down its performance a bit as the contents of the old Array must be copied to a new Array.

At the same time, it's compulsory to specify the size of an Array directly or indirectly while creating it. And also Arrays can store both primitives and objects while ArrayLists only can store objects.

Ref: https://bit.ly/3o8L2KH